Engine operation includes a combustion process and an exhaust process. During the combustion process, an air/fuel mixture is combusted within cylinders to drive pistons (not shown). A vehicle engine produces exhaust as a result from the combustion of air and fuel. During the exhaust process, exhaust is released from the cylinders into the exhaust system. The exhaust contains Nitrous Oxide (NOx) and Carbon Monoxide (CO) that is treated before the exhaust is released from the vehicle.
An exhaust treatment system is used to reduce the amount of emissions (e.g., NOx) in the exhaust. A control module monitors engine operation and emissions levels and a dosing system injects a reducing agent into the exhaust upstream from a catalyst. The treated exhaust reacts with the catalyst and a chemical reaction occurs that reduces the level of emissions.
The dosing system includes a dosing agent supply and an injector. The dosing agent must be delivered in a proper amount corresponding to the level of emissions in order to effectively treat the exhaust. A faulty injector or an insufficient dosing agent supply would result in an inadequate amount of dosing agent to properly treat the exhaust. Therefore, it is desirable to monitor the dosing system and determine whether it is operating correctly.